(1) Field of the Invention
The present invention relates to an organic electro-luminescence (EL) display device capable of emitting light in multiple colors.
(2) Description of the Related Art
A display panel (organic EL display) using an organic light-emitting unit (Organic Light-Emitting Diode: OLED) has been known as a display panel using current-driven light-emitting material. Since the display panel has advantages such as good viewing angle characteristics and small power consumption, the display panel has been attracting attention as a candidate for a next-generation flat panel display.
As a configuration of the display panel using the organic light-emitting unit, a configuration in which pixels each having organic light-emitting units each of which is formed with organic light-emitting material which emits light in blue, green, or red are arranged in a matrix or a delta shape on an entire surface has been proposed.
In this configuration, each pixel has a color filter of a different color for each of the colors of light emitted, and a configuration with a light-blocking property by the color filters included in the two pixels or three pixels neighboring the non light-emitting region of each pixel overlapping with each other has been proposed (see Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2003-234186). With this configuration, it is possible to secure the light-blocking property at the non light-emitting region without forming a filter known as a black matrix for suppressing the reflection of external light above the non light-emitting region. In other words, it is possible to secure the light-blocking property of the non light-emitting region with a simple configuration.
Furthermore, a configuration in which each pixel includes color filters different for each color of the light emitted, and a black matrix above the non light-emitting region, and a red color filter which transmits red light and a blue color filter which transmits blue light are arranged at a position corresponding to an active element on the black matrix (see Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2005-99393). With this configuration, compared to the case in which only the black matrix is provided above the non light-emitting region, the light-blocking property of the light-emitting region is further improved, suppressing malfunction of the active elements and suppressing the reduction in the display quality.
Furthermore, another configuration in which a red color filter transmitting red light is formed above the light-emitting region of red, and a blue color filter transmitting blue light is formed above the blue light-emitting region, and no color filter is arranged above the green light emitting region has been proposed. (see Patent Literature 3: Japanese Unexamined Patent Application Publication No. 2002-373776). According to this configuration, it is possible to improve the contrast with less number of patterning.
Here, contrast represents a ratio of luminance in the non light-emitting region to the luminance in the light-emitting region (luminance of light-emitting region divided by luminance of non light-emitting region). When the luminance of the non-light emitting region is high due to reflected external light, the contrast is inherently low, and the display device cannot display a sharp image. On the other hand, when the luminance of the non-light emitting region is low, the contrast is high, and deeper black can be displayed, allowing the display device to display a sharp image.